描述
Grade 420J2 is a martensitic stainless steel with chromium content around 12-14% and carbon content roughly 0.26-0.40%.
When properly heat-treated (quenched and tempered), it achieves high hardness and good wear resistance.
It offers good corrosion resistance in mild atmospheres, domestic and industrial environments; resistant to diluted nitric acid, carbonic acid, ammonia, detergent solutions, vinegar, some petroleum products and steam.
Compared to austenitic stainless steels (e.g., 304, 316), its corrosion resistance is moderate – in chloride-rich or aggressive environments it is more vulnerable.
For cold-rolled or cold-processed forms, formability and weldability are somewhat limited: the higher carbon makes welding riskier (cold cracking) and heavy cold deformation may lead to cracking or brittleness if not properly tempered.
Applications
Knife blades, scissors, kitchen cutlery, budget diving knives, domestic shears – where hardness, wear resistance and some corrosion resistance are required.
Medical instruments such as surgical blades can use 420J2, although manufacturing challenges (welding/processing) may limit its use.
Industrial components: pump and valve parts, automotive components, wear parts – when strength, wear resistance and moderate corrosion protection are desired.
